Methods for cooling measuring devices in high temperature wells

Abstract

A method for monitoring a fracturing operation in a target well comprising extending a seismic sensor in a tubing string to a first position in an well offset from the target well. A coolant fluid is circulated through the tubing string for a predetermined time. The tubing string is retracted to a second uphole position such that the cooled seismic sensor is exposed in the offset wellbore. A seismic signal emitted during the fracturing operation of the target well is sensed in the offset well.

The invention claimed is: 
     
       1. A method for monitoring, a fracturing operation in a target well comprising:
 a. extending at least two spaced apart seismic sensors in a tubing string to a first position in a well offset from the target well; 
 b. circulating a coolant fluid from the surface through the tubing string for a predetermined cooling time to cool the at least two seismic sensors; 
 c. retracting the tubing string to a second uphole position such that the cooled at least two seismic sensors are exposed in the offset well and stopping the coolant flow during a predetermined heat up time; 
 d. sensing a seismic signal emitted during the fracturing operation in the target well while the coolant circulation is stopped during the predetermined heat up time; 
 e. re-extending the tubing string over the at least two seismic sensors at the first position in the well after the predetermined heat up time; 
 f. restarting circulation of the cooling fluid from the surface through the tubing string for the predetermined cooling time to cool the at least two seismic sensors; 
 g. retracting the tubing string to the second uphole position such that the cooled at least two seismic sensors are exposed in the offset well and stopping the coolant flow during a predetermined heat up time; 
 h. sensing the seismic signal emitted during the fracturing operation in the target well while the coolant circulation is stopped during the predetermined heat up time; and 
 i. repeating steps e-h until the fracturing operation is complete. 
 
     
     
       2. The method of  claim 1  wherein the coolant fluid is selected from the group consisting of: water, a water based drilling fluid, water with a friction reducing agent, a brine, and a potassium chloride (KCl)-brine solution. 
     
     
       3. The method of  claim 1  further comprising modeling the thermal transport process to determine the predetermined cooling time and the predetermined heat up time. 
     
     
       4. A method for monitoring a fracturing operation in a target well comprising:
 a. extending at least two spaced apart seismic sensors in a tubing string to a first position in a well offset from the target well; 
 b. circulating a coolant fluid through the tubing string until a temperature sensor associated with at least one of the at least two seismic sensors reaches a predetermined cooled operating temperature; 
 c. retracting the tubing string to a second uphole position such that the at least two seismic sensors are exposed in the offset well and stopping the coolant circulation; 
 d. sensing a seismic signal emitted during the fracturing operation in the target well while the coolant circulation is stopped; 
 e. monitoring the temperature sensor associated with at least one of the at least two seismic sensors and determining when the sensed temperature reaches a predetermined maximum operating temperature; 
 f. re-extending the tubing string over the at least two seismic sensors at the first position in the well when the sensed temperature reaches the predetermined maximum allowable operating temperature; 
 g. restarting circulation of the coolant fluid through the tubing string until the sensed temperature reaches the predetermined cooled operating temperature; 
 h. retracting the tubing string to the second uphole position such that the at least two seismic sensors are exposed in the offset well and stopping the coolant flow; 
 i. sensing the seismic signal emitted during the fracturing operation in the target well while the coolant circulation is stopped until the sensed temperature exceeds the predetermined maximum allowable operating temperature; and 
 j. repeating steps e-i until the fracturing operation is complete. 
 
     
     
       5. The method of  claim 4  wherein the coolant fluid is selected from the group consisting of: water, a water based drilling fluid, water with a friction reducing agent, a brine, and a potassium chloride (KCl)-brine solution. 
     
     
       6. The method of  claim 5  further comprising modeling the thermal transport process to determine a cool down time and a heat up time for a selected coolant. 
     
     
       7. A method for logging a high temperature well comprising:
 a. extending at least one logging tool in a tubing string to a first position in the high temperature well; 
 b. circulating a coolant fluid through the tubing string until a temperature sensor associated with the logging tool reaches a predetermined cooled operating temperature; 
 c. retracting the tubing string to a second uphole position such that the at least one logging tool is exposed in the well and stopping the coolant circulation; 
 d. sensing a formation parameter of the surrounding formation while the coolant circulation is stopped; 
 e. monitoring the temperature sensor associated with the logging tool and determining when the sensed temperature reaches a predetermined maximum allowable operating temperature; 
 f. re-extending the tubing string over the logging tool at the first position when the sensed temperature reaches the predetermined maximum allowable operating temperature; 
 g. restarting circulation of the coolant fluid through the tubing string until the sensed temperature reaches the predetermined cooled operating temperature; 
 h. retracting the tubing string to the second uphole position such that the logging tool is exposed in the well and stopping the coolant circulation; 
 i. sensing the formation parameter in the well while the coolant circulation is stopped; and 
 j. repeating steps e-i until the logging operation is complete. 
 
     
     
       8. The method of  claim 7  wherein the coolant fluid is selected from the group consisting of: water, a water based drilling fluid, water with a friction reducing agent, a brine, and a potassium chloride (KCl)-brine solution. 
     
     
       9. The method of  claim 7  wherein the logging tool is selected from the group consisting of: a resistivity tool, a nuclear porosity tool, a nuclear density tool, a magnetic resonance tool, a directional tool, and a formation test tool.